index.html

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>tree</title>
  <meta name="viewport" content="width=device-width,initial-scale=1.0,maximum-scale=1.0,minimum-scale=1.0,user-scalable=no">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
  <meta name="format-detection" content="email=no" />
  <meta name="format-detection" content="telephone=no">  
  <meta name="apple-mobile-web-app-capable" content="yes">
  <meta name="apple-mobile-web-app-status-bar-style" content="black">
  <meta http-equiv="Content-Type" content="text/html">
  <meta name="full-screen" content="yes">
  <meta name="browsermode" content="application">
  <meta name="x5-orientation" content="portrait">
  <meta name="x5-fullscreen" content="true">
  <meta name="x5-page-mode" content="app">
  <meta name="msapplication-tap-highlight" content="no">
  <script>
    (function (doc, win) {
      var docEl = doc.documentElement,
        resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
        recalc = function () {
          var clientWidth = docEl.clientWidth;
          if (!clientWidth) return;
          docEl.style.fontSize = 20 * (clientWidth / 1400) + 'px';
        };

      if (!doc.addEventListener) return;
      win.addEventListener(resizeEvt, recalc, false);
      doc.addEventListener('DOMContentLoaded', recalc, false);
    })(document, window);
  </script>
</head>

<body>
  <div id="app"></div>
  <!-- built files will be auto injected -->
</body>

</html>